At the risk of getting my fingers chopped off for asking. Could anyone provide an update on the new Fly by wire custom LNAV update? Or when it will be implemented into the development or experimental builds?
In my opinion its going to be one of the single biggest improvements to the Sim to date!
I’m jealous from watching my favourite Youtubers who’ve been reviewing advanced copies of it!
I am looking every day for an answer to this?
I believe the ETA for the FBW A32NX LNAV update is it will be released when it’s done and thoroughly tested to be at an acceptable level with few bugs.
It’s out on experimental branch as of a few hours ago
Just updated to experimental and it seems vastly improved, thanks for the heads up. Now, where’s that VNAV…?
Sadly mine crashed to desktop as soon as I moved into climb detent. Oh well, lets give it another go!
Fixing the LNAV is far more important than the VNAV. VNAV you can do without. LNAV on the other hand is very much essential
I don’t disagree whatsoever, though now LNAV is gaining traction and (almost) feels fairly representative of the real aircraft, I’m just hoping VNAV won’t be too far off. The FPM is still doing some funky things, but I know the team are aware of this.
Correct me if I’m wrong, but isn’t LNAV is only for laternal navigation only? I mean, if we set the aircraft to managed NAV mode, currently it’s already doing the laternal navigation part. My question here is, how come LNAV is considered to be not working while if I try using managed NAV mode, it follows my flight plan already.
We do know that the VNAV isn’t working, and I’ve been doing semi-automatic descent using the managed DES mode or FPA descent. But what’s the difference between a fully working LNAV versus the managed NAV mode that we already have right now?
LNAV is not just following the way points.. It also needs to be able to follow SIDS’s and STARS as well, which the default system is not capable of. That’s why it just goes Direct to the runway. With proper LNAV
things like this become possible. The red Line indicates what the default stuff does, which is wrong!
Which then means you can actually fly approaches correctly
The default LNAV will insert garbage USR/USER waypoints which are not realistic, and the AP wont respect the the correct Path.
And as you can see, the correct Altitudes are on the chart, so you just need to make sure you respect them which is what VNAV can do among other things, but doing VNAV yourself is a lot easier than LNAV
Not trying to teach you how to suck eggs, but if you are asking the question, I feel like you dont fully understand how important LNAV is.
In Summary the default LNAV will not respect approaches and Departures correctly, among other things, but critically its approaches / STARS. In the last Image, with proper LNAV the plane will hit all those points if that approach is selected
FLYERS - FLICR - etc.. CONDY is the where the Platform Alt 3800 is, and this is the start of the ILS Capture. You will see between HAWKO and BJORG there is a mandatory alt restriction of 4700 VNAV would help with that, but as a pilot you can also do that quite easily, using the various methods, VS/FPA or even OP DESC. Trying to do this without LNAV or with those stupid USR/USER way points is impossible.
I see… interesting.. I’ve always set the SIDs and STARs on my flight plan and my autopilot always follows the pattern according to it just fine. Well, unless I got those little weird bugs but they only happen once or twice.
I thought that if the autopilot isn’t following the right pattern, it’s just simply means the pattern itself is wrong. But I guess it could affect either way just fine.
And I was under the impression that the LNAV function that the FBW team is working on is simply “fixing the bugs” that the default Asobo NAV mode has since every time I set a SID and STAR into my flight plan my autopilot follows them 95% of the time except for those times when I got some minor bugs that I can mitigate quite easily. (I think of it as a instrument failure that I need to take control manually).
LNAV? Sure would be great. But the thing that makes an Airbus an Airbus has been missing for far too long. And it isn’t LNAV or VNAV. it’s called “managed” modes. Make this work and we’ll have a proper Airbus.
Really? I get it’s important but lateral guidance is pretty basic functionality for even your basic 172. Handling managed descents (it isn’t called VNAV) to an airport with a complex STAR is what makes the magic of the Airbus. Getting managed modes right in the Airbus is inclusive of lateral and vertical. There is no one mode more important than the other. It’s the basic DNA of the A320.
Agree. Not sure what I’m missing either. I’ve had no issues with lateral guidance in the A32NX outside of known missing bits.
Now the bit about stringing together the STAR properly I agree with. It’s not working properly so I often have to manually string together the transition from the STAR to the approach. This is where the MCDU is supposed to build in a DISCONTINUITY that you have to “close” with the approach transition. Current aircraft doesn’t do this.
It’s still not more important than overall managed modes as both are vital to a proper representation of the Airbus. Of all the things to not implement in an Airbus, this capability was not one of them.
Offering a different perspective, you can build the waypoints manually in the MCDU and have it follow the STAR. You can also pull that heading knob and go into HDG mode and follow the path.
Doing the calculations to hit multiple altitude and speed restrictions on a STAR, In my opinion, is much more complicated - whether in a Boeing or an Airbus. It’s why STARs require RNAV capabilities, not manual calculations to “wing it” on the arrival.
@Fmgc320 Out of curisoty, do you have real world experience with aircraft FMS solutions ?
I do not mean this in any snarky way, but it seems to me you misunderstand how those things are integrated.
As someone who has spent the better part of the last 3 months working on this update to the FMS, I can tell you it’s not just a matter of implementing the managed modes.
First of all, for that to even be possible in the first place, you need to design a system that stores flight plan leg data in the same way the IRL FMS does. You cannot do proper VNAV by storing a list of fixed waypoints like the stock aircraft and a lot of payware addons do.
We’ve spent a LOT of time studying the inner workings of the A320 FMS to come up with a proper design and we are still facing design challenges that require constant tweaking and re-design of some areas. Implementing an aircraft that flies the route realistically is not an easy task - and getting LNAV right in the first place is an essential pre-requisite of making VNAV work.
The FMS dynamically generates the lateral and vertical paths using dozens of parameters that often have recursive or bidirectional dependencies on other parts of the flight plan. This require considerable time to develop. There are more than 10 different leg types and 100+ combinations that generate differing transitions between paths with some of them having more than 10 edge cases depending on leg parameters.
Now, we could develop a “good enough” system that plots a somewhat accurate ToD waypoint and call that VNAV, but the aim of the A32NX project is not to make a “good enough” A320.
Things have to be developed in order and correctly to one day be great.
No snark detected and I actually 100% agree with you. Let me be clear that I commend you and the team for what you provide to the community. I know it’s very difficult. It’s actually part of the point of why I was concerned with Asobo putting an A320 in the sim in the first place. Its my favorite aircraft and I’ve been flying nearly every iteration of it on every flight simulator platform (“legacy” flight simulator, P3D, X-Plane) and I’ve seen nearly all struggle with the managed flight and FBW systems of the A320. It’s no easy kit. Only a few have really nailed it, in my opinion.
I don’t have “real world” FMS experience. I fly the G1000 172 IRL. I’ve studied the real-word manuals of the THALES systems and Honeywell/Pegasus FMS systems for Boeing to understand how they function, not how they are programmed. That’s certainly a task for you and other talented developers.
My point was just stating that both are important, as you know, to fully deliver overall managed functionality for the A320. No argument on the difficulty or what comes first. You know what needs to be done and I’m certainly not disputing the difficulties. Again, thank for your efforts.
Thank you for understanding how much work goes into this, really.
We’ll get to a very high level of accuracy and the technical references we have will comfortably put us above any reproduction of the A320 FMS that has ever been made - it’s just a lot of things to program and the design choices to make everything work are incredibly hard to make.
I hope you are satisfied with the upcoming progress, there’s a lot of work going into it and we hope that within a certain time frame it’ll be up there with the highest fidelity addons.
We have to give credit where it’s due and yes, I’ve been impressed since the day your team took on this project. In my opinion I can get similar enjoyment out of it as I would with one of my pricey add-ons in the other platforms. You guys are on it, no doubt.
BTW, my long time gamertag should be a dead giveaway as to the fondness I hold for Airbus! 
